1. Field of the Invention
The present invention relates generally to window blinds and, more specifically, to a window blind cutting machine for cutting window blinds to the desired length.
2. Description of the Related Art
Window blind manufacturers provide only a limited number of sizes (the length of the headrail, bottom rail, and slats) for each model, and the retailers or upholsterers cut the window blinds to the desired sizes by means of a window blind cutting machine when selling or installing the window blinds.
The members of a window blind have two end structures made symmetrical for the insertion of cord members. When cutting the members of a window blind, the two ends of the members must be equally cut, keeping the ends symmetrical.
U.S. patent publication No. 2002/178884 discloses an advanced window blind cutting machine, which comprises two cutters transversely movably mounted at two ends of the machine base. The members of the window blind are put on the machine base and extended along the length of the machine base. The two ends of the machine base are respectively equipped with a respective outwardly extended measuring rule for measuring the size of the part to be cut. During cutting, the members of the window blind can be moved longitudinally from one end of the machine base to the other, for enabling the both ends of the members of the window blind to be cut by the cutters.
According to the aforesaid cutting method, the operator calculates the length to be cut off subject to the actual length of the window blind and the desired window blind size. For example, when wishing to cut a window blind of 31.5 inches to 28 inches, the operator calculates the length difference between the original length of the window blind and the desired window blind size to obtain the size to be cut at each other, i.e., (31.5−28)/2=1.75 inches. A minor calculation error may cause the window blind to be improperly cut. In this case, a secondary processing process is necessary. If the both ends of the members of the window blind are cut over the accurate size, the window blind becomes not in conformity with the desired specifications and not usable.